1. Field of the Invention
Embodiments of the present disclosure generally relate to renewable energy power systems and, more particularly, to a method and apparatus for detecting series and parallel DC arc faults in a DC circuit of a photovoltaic (PV) system.
2. Description of the Related Art
Solar modules have historically been deployed in mostly remote applications, such as remote cabins in the wilderness or satellites, where commercial power was not available. Due to the high cost of installation, solar modules were not an economical choice for generating power unless no other power options were available. However, the worldwide growth of energy demand is leading to a durable increase in energy cost. In addition, it is now well established that the fossil energy reserves currently being used to generate electricity are rapidly being depleted. These growing impediments to conventional commercial power generation make solar modules a more attractive option to pursue.
Solar modules, or photovoltaic (PV) modules, convert energy from sunlight received into direct current (DC). The PV modules cannot store the electrical energy they produce, so the energy must either be dispersed to an energy storage system, such as a battery or pumped hydroelectricity storage, or dispersed by a load. One option to use the energy produced is to employ inverters to convert the DC current into an alternating current (AC) and couple the AC current to the commercial power grid. The power produced by such a distributed generation (DG) system can then be sold to the commercial power company, or used to offset local consumption of electricity by local loads.
In order to mitigate potential safety hazards during such DC to AC power conversion, a DC circuit of the PV system must often be protected with fuses, and specific system design constraints must be followed. In addition, a Ground Fault Detection and Interruption circuit is often required. Such protective measures may also be utilized in DC/DC power converters. These protective measures, however, do not provide reliable detection or mitigation of DC arc faults during power conversion (i.e., DC/DC or DC/AC power conversion). Such arcs are extremely dangerous, as the DC PV system will continue to provide energy into a short circuit or an arcing circuit as long as the PV modules continue to be irradiated with light, potentially leading to a fire.
Therefore, there is a need for a method and apparatus for automatically detecting series and parallel DC arc faults and extinguishing those arcs.